C3A, Spain

Picture courtesy of Nieto Sobejano Arquitectos. Copyright 2012-13 Roland Halbe

Four years after completion, the museum and artistic education centre C3A in Córdoba, Spain, designed by architects Nieto Sobejano Arquitectos, was officially opened on 19 December. The building’s artistic façade installation implemented by realities:united showed the German studio for art and architecture’s animation sequence BREEZE during the opening ceremony.

The original concept for the building by Nieto Sobejano Arquitectos proposed the integration of a low-resolution light and media façade on the building surface, facing the Río Guadalquivir. realities:united was commissioned to further develop the conception and the design for this media skin in close cooperation with the architects.

As part of its competition design for the C3A, Nieto Sobejano had proposed a medial enhanced design that was inspired by realities:united’s very first dynamic façade design (BIX Communicative Display Skin for Peter Cook’s Kunsthaus in Graz, 2003). The competition design featured a concrete façade with a regular grid of circular openings, each one to be equipped with a circular fluorescent light tube.

After winning the competition, Nieto Sobejano contacted the studio to get the team on board for further development of the project.

‘‘In this way we were first commissioned by the local government (Junta de Andalucia en Córdoba) in 2006 for the concept development and design of the façade, followed by a commission by Nieto Sobejano Arquitectos for the planning and artistic site supervision, and a commission by the general contractor FCC Construccion S.A. for the development of the artistic software,’’ explained Tim Edler, Co-Founder of realities:united.

Following a period of collaboration and cooperation with the architects, C3A’s façade has now been transformed into a light and media display, whilst maintaining  its solid appearance as envisioned by the architects.

The resultant exterior has been designed to deliver a tactile and solid appearance in the day, while turning into a unique and dynamic communication wall that reacts very specifically to the architecture at night.

The starting point for the media façade was an analysis of the significant inner structure of the building, which is made up of a tessellated pattern of polygonal rooms.

This inner motif is translated to form a characteristic outer topography on the façade, a system of irregularly shaped, hexagonal indentations of varying density, size and scale.

There are 1,319 of these pre-fabricated ‘bowls’ scattered over the 100-metre long fiberglass-reinforced cement (GRC) façade. Each of the bowls serves as a reflector for an integrated artificial light source. By controlling the intensity of each lamp individually, the bowls turn the façade into a low-resolution grey scale display.

Three different scales of bowls are employed and distributed in huge patterns over the total exterior, thereby subtly echoing the building’s architectural elements. Additionally, each bowl appears to be unique in shape and size; and their distribution appears to be irregular, with only the distribution density remaining consistent.

‘‘The effectiveness of façade lighting is dependent on the quality and efficiency of the luminaires used and designing the right lighting control system,’’ said Jan Riha of Lledó Lighting Group, the company that developed the fixtures, wiring and control scheme for the project.

Each of the bowls is illuminated from the side and serves as a reflector for the integrated LED mini spotlights, of which the intensity can be controlled individually. One of the challenges faced was the uniformity of the illumination, as the bowls vary in size. In relation to this, the mini spotlights used have been applied in relation to the size of bowl in which they are situated. The innovation lies in Lledó’s inhouse developed optical concept which combines lens and light-shaping diffuser film and the flush mounted frosted cover glass.

‘‘For this project we have chosen mini spot lights equipped with a single high power LED with 2.1W 86 lm/W, and a special oval lighting distribution to obtain the adequate distribution for each bowl type,’’ explained Riha.

The square shape of the heat sink provides an optimal heat disipation for the LED. In addition, the IP65 fixtures are telescopic and the fact that it is easy to swivel and tilt, aids the aiming of the light.

Just like the human eye’s retina, this composition allows the definition of areas of varying density or sensitivity on the façade. This analogy offers a certain artistic freedom: the resolution of the displayed images can stay low, fitting the blown-up scale of the screen, creating a mode of display in which the motifs are hinted at, rather than unambiguously presented.

‘‘We could never verify that this principle would work on the scale of the façade without building a one-to-one prototype,’’ commented Edler. ‘‘Of course we tried to simulate the anticipated effect to a certain degree and we developed an advanced software to run the façade, but testing it for the very first time remained a very exciting moment.’’

During the day, the exterior shows a three-dimensional landscape with no sign of being a media façade. Additionally, this tectonically modulated surface topography is characterised by a playful composition of light and shadow that constantly changes with the movement of the sun. The thorough immersion of the pixel-bowls – like negative impressions – in the volume of the façade turns the architectural scheme itself into a digital information carrier.

The studio’s interest in the aspect of visual acuity stems from earlier projects and extensive research on the process of visual perception. For visualisations with very low resolution, the precognition of the brain determines whether an image or animation can be recognised. A motif that has been displayed at a higher resolution can be shifted to much lower resolution and still preserve its readability.

The C3A project was the studio’s first commission to transform a non-transparent façade to become dynamic. ‘‘In comparison to all other dynamic façades we developed, this was a game changer. At least if you want or need to work with light as a medium – it was tricky to preserve the building’s solid appearance as a concrete block, as planned by Nieto Sobejano, while turning its main façade into an urban communication tool,’’ said Edler.

For that reason, realities:united changed the basic principle of the façade by transforming it into a tactile topography made out of recesses to be illuminated from the side rather than perforating it like Swiss cheese as proposed by the architects. In conclusion, this works very well; when you approach the building during the day, you discover a solid concrete façade with a playful texture of sunlight and shadow. Only at night the special qualities of the façade are revealed.

When asked about the role lighting plays in this project Edler responded: ‘‘I believe it’s not so much about the right lighting but about the identification of a suitable artistic concept to match the architecture.’’ For instance, besides the solid appearance of the façade, the decision to make use of the building’s significant inner structure and its tessellated pattern of polygonal rooms.

Upon reflection, Edler and the realities:united team claim their biggest challenge was to trust their own concept until the very end. ‘‘We proposed different scales of pixels on the façade in order to engineer a façade that could display images with as little pixels as possible that are still decipherable by the observer,’’ concluded Edler.